Placement of virtual machines on physical hosts based on collocation rules

ABSTRACT

Placement of virtual machines on physical hosts is based on collocation rules with situational enforcement policies set by a system administrator to increase flexibility in rule enforcement and to more efficiently utilize system resources. A scheduler mechanism allows a system administrator to select different collocation rules and situational enforcement policies for a group of virtual machines. The scheduler mechanism utilizes the collocation rules and the situational enforcement policies to place the virtual machines.

BACKGROUND 1. Technical Field

This invention generally relates to virtual machines in a computingenvironment, and more specifically relates to placement of virtualmachines on physical hosts based on collocation rules with situationalpolicies for hard and soft enforcement of the collocation rules.

2. Background Art

Cloud computing is a common expression for distributed computing over anetwork and can also be used with reference to network-based servicessuch as Infrastructure as a Service (IaaS). IaaS is a cloud basedservice that provides physical processing resources to run virtualmachines (VMs) as a guest for different customers. The virtual machinemay host a user application or a server.

A computing environment, such as a cloud computing environment, may havea large number of physical machines that can each host one or morevirtual machines. Prior art cloud management tools allow a systemadministrator to select collocation rules that determine the placementof virtual machines on a physical host in relation to other virtualmachines. Collocation rules include affinity rules and anti-affinityrules. Affinity rules specify a relationship how a virtual machine isplaced with related virtual machines in a group of virtual machines on ahost or set of hosts. Similarly, anti-affinity rules specify how avirtual machine is not to be placed with other virtual machines on thesame host or cluster of hosts. In some prior art systems the systemadministrator is also able to select how all the collocation rules areenforced. Strictly enforced rules are called hard rules, and rules thatare not strictly enforced are called soft rules.

BRIEF SUMMARY

An apparatus and method place virtual machines on physical hosts basedon collocation rules with situational enforcement policies set by asystem administrator to more efficiently utilize system resources. Ascheduler mechanism allows a system administrator to select differentcollocation rules and situational enforcement policies for a group ofvirtual machines. The scheduler mechanism utilizes the collocation rulesand the situational enforcement policies to place the virtual machinesfor one or more host groups.

The foregoing and other features and advantages of the invention will beapparent from the following more particular description of preferredembodiments of the invention, as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The disclosure will be described in conjunction with the appendeddrawings, where like designations denote like elements, and:

FIG. 1 is a block diagram of a cloud computing node;

FIG. 2 is a block diagram of a cloud computing environment;

FIG. 3 is a block diagram of abstraction model layers;

FIG. 4 is a block diagram that illustrates a scheduler mechanism asdescribed herein that places virtual machines on physical resourcesbased on collocation rules with situational enforcement policies set bya system administrator;

FIG. 5 is a table that illustrates some examples of collocation rulesand situational enforcement policies;

FIG. 6 is a flow diagram of a method for placement of virtual machineson physical resources based on collocation rules with situationalenforcement policies set by a system administrator as described herein;and

FIG. 7 is a flow diagram of an example method for step 630 in FIG. 6.

DETAILED DESCRIPTION

The claims and disclosure herein provide an apparatus and method forplacing virtual machines on physical hosts based on collocation ruleswith situational enforcement policies set by a system administrator toincrease flexibility in rule enforcement and more efficiently utilizesystem resources. A scheduler mechanism allows a system administrator toselect different collocation rules and situational enforcement policiesfor a group of virtual machines. The scheduler mechanism utilizes thecollocation rules and the situational enforcement policies to place thevirtual machines.

It is understood in advance that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based email). Theconsumer does not manage or control the underlying cloud infrastructureincluding network, servers, operating systems, storage, or evenindividual application capabilities, with the possible exception oflimited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forloadbalancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 1, a block diagram of an example of a cloudcomputing node is shown. Cloud computing node 100 is only one example ofa suitable cloud computing node and is not intended to suggest anylimitation as to the scope of use or functionality of embodiments of theinvention described herein. Regardless, cloud computing node 100 iscapable of being implemented and/or performing any of the functionalityset forth hereinabove.

In cloud computing node 100 there is a computer system/server 110, whichis operational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 110 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, handheld or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 110 may be described in the general context ofcomputer system executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 110 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 1, computer system/server 110 in cloud computing node100 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 110 may include, but are notlimited to, one or more processors or processing units 120, a systemmemory 130, and a bus 122 that couples various system componentsincluding system memory 130 to processor 120.

Bus 122 represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnect (PCI) bus.

Computer system/server 110 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 110, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 130 can include computer system readable media in the formof volatile, such as random access memory (RAM) 134, and/or cache memory136. Computer system/server 110 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 140 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 122 by one or more datamedia interfaces. As will be further depicted and described below,memory 130 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions described in more detail below.

Program/utility 150, having a set (at least one) of program modules 152,may be stored in memory 130 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 152 generally carry out the functionsand/or methodologies of embodiments of the invention as describedherein.

Computer system/server 110 may also communicate with one or moreexternal devices 190 such as a keyboard, a pointing device, a display180, a disk drive, etc.; one or more devices that enable a user tointeract with computer system/server 110; and/or any devices (e.g.,network card, modem, etc.) that enable computer system/server 110 tocommunicate with one or more other computing devices. Such communicationcan occur via Input/Output (I/O) interfaces 170. Still yet, computersystem/server 110 can communicate with one or more networks such as alocal area network (LAN), a general wide area network (WAN), and/or apublic network (e.g., the Internet) via network adapter 160. Asdepicted, network adapter 160 communicates with the other components ofcomputer system/server 110 via bus 122. It should be understood thatalthough not shown, other hardware and/or software components could beused in conjunction with computer system/server 110. Examples, include,but are not limited to: microcode, device drivers, redundant processingunits, external disk drive arrays, RAID systems, tape drives, dataarchival storage systems, etc.

Referring now to FIG. 2, illustrative cloud computing environment 200 isdepicted. As shown, cloud computing environment 200 comprises one ormore cloud computing nodes 100 with which local computing devices usedby cloud consumers, such as, for example, personal digital assistant(PDA) or cellular telephone 210A, desktop computer 210B, laptop computer210C, and/or automobile computer system 210N may communicate. Nodes 100may communicate with one another. They may be grouped (not shown)physically or virtually, in one or more networks, such as Private,Community, Public, or Hybrid clouds as described hereinabove, or acombination thereof. This allows cloud computing environment 200 tooffer infrastructure, platforms and/or software as services for which acloud consumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 210A-Nshown in FIG. 2 are intended to be illustrative only and that computingnodes 100 and cloud computing environment 200 can communicate with anytype of computerized device over any type of network and/or networkaddressable connection (e.g., using a web browser).

Referring now to FIG. 3, a set of functional abstraction layers providedby cloud computing environment 200 (FIG. 2) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 3 are intended to be illustrative only and the disclosure andclaims are not limited thereto. As depicted, the following layers andcorresponding functions are provided.

Hardware and software layer 310 includes hardware and softwarecomponents. Examples of hardware components include mainframes 352; RISC(Reduced Instruction Set Computer) architecture based servers 354;servers 356; blade servers 358; storage devices 360; and networks andnetworking components 362. In some embodiments, software componentsinclude network application server software 364 and database software366.

Virtualization layer 320 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers368; virtual storage 370; virtual networks 372, including virtualprivate networks; virtual applications and operating systems 374; andvirtual clients 376.

In one example, management layer 330 may provide the functions describedbelow. Resource provisioning 378 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 380provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 382 provides access to the cloud computing environment forconsumers and system administrators. Service level management 384provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 386 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA. The management layer further includes ascheduler mechanism (SM) 350 as described herein. While the SM 350 isshown in FIG. 3 to reside in the management layer 330, the SM 350actually may span other levels shown in FIG. 3 as needed.

Workloads layer 340 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 386; software development and lifecycle management 390;virtual classroom education delivery 392; data analytics processing 394;transaction processing 396 and mobile desktop 398.

As will be appreciated by one skilled in the art, aspects of thisdisclosure may be embodied as a system, method or computer programproduct. Accordingly, aspects may take the form of an entirely hardwareembodiment, an entirely software embodiment (including firmware,resident software, micro-code, etc.) or an embodiment combining softwareand hardware aspects that may all generally be referred to herein as a“circuit,” “module” or “system.” Furthermore, aspects of the presentinvention may take the form of a computer program product embodied inone or more computer readable medium(s) having computer readable programcode embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a non-transitory computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer readable storage medium would include the following: anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, a portable compact disc read-only memory(CD-ROM), an optical storage device, a magnetic storage device, or anysuitable combination of the foregoing. In the context of this document,a computer readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Referring now to FIG. 4, a block diagram illustrates a schedulermechanism 350 (shown in FIG. 3 and introduced above) that performsplacement of virtual machines (VMs) on physical resources based oncollocation rules and situational enforcement policies. In theillustrated example, the scheduler mechanism 350 is part of a cloudmanager 410. The cloud manager 410 may be similar to cloud managersknown in the prior art but includes the additional features of thescheduler mechanism 350 as described herein. The cloud manager 410allows a human user or system administrator 414 to set up and managecomputer resources 420 through a user interface 416. The cloud manager410 implements the cloud management functions 330 described above withreference to FIG. 3. The scheduler mechanism 350 includes an optimizer412. The optimizer 412 works in conjunction with the scheduler mechanism350. The optimizer 412 may operate similarly to prior art optimizersexcept as described herein. The optimizer 412 monitors VM and hostperformance to determine when migration needs to occur and supports thescheduler mechanism 350 in migrating VMs to other hosts according topolicies set by a system administrator. The operation of the schedulermechanism 350 is described further below.

Referring again to FIG. 4, the cloud manager 410 allows the systemadministrator 414 to set up and manage hardware computer resources 420.Computer resources 420 represent computer resources such as physicalhost computer systems in a cloud computing environment. In theillustrated example, the computer resources 420 host two groups ofvirtual machines, VM Group1 430 and VM Group2 440. A VM group is alogical grouping of one or more virtual machines managed by the cloudmanager 410. The computer resources 420 may include a large number ofphysical computer hosts (not shown) arranged into one or more hostgroups. The virtual machine groups may be hosted on one or more physicalhosts in the host groups. The physical computer hosts in the computerresources 420 may be located remotely from the cloud manager 410. A hostis a physical computer accessible over a network to the cloud manager410. A host has a hypervisor (software) that allows the host to run oneor more virtual machines as known in the prior art.

As shown in FIG. 4, VM Group1 430 has a collocation rule 432 andsituational enforcement policies 434. Similarly, VM Group2 440 has acollocation rule 442 with situation enforcement polices 444. In FIG. 4,the collocation rules 432,442 and situational enforcement policies 434,444 are shown within their respective VM group for illustrationpurposes. The collocation rules 432,442 and situational enforcementpolicies 434, 444 are logically associated with the respective VM groupas shown. However, the collocation rules 432, 442 and situationalenforcement policies 434, 444 may physically reside in any suitablelocation such as in memory, a file or a table assessable to thescheduler mechanism 350.

As discussed above, the scheduler mechanism 350 provides placement ofvirtual machines on physical computer resources based on collocationrules and situational enforcement policies set by a systemadministrator. Examples of collocation rules are affinity andanti-affinity. An affinity rule specifies a relationship where a virtualmachine is placed with related virtual machines in a group on one ormore physical hosts. Similarly, an anti-affinity rule specifies that avirtual machine is not to be placed with other virtual machinesbelonging to the same group on the same physical host. A situationalenforcement policy as used herein means a situation or set ofcircumstances where a policy dictates whether to invoke hard or softenforcement of the collocation rule. Hard enforcement of a rule meansthat the collocation rule (affinity or anti-affinity) is strictlyenforced despite the circumstances or situation. Conversely, softenforcement of a rule means the collocation rule may not necessarily beenforced, and thus placement of the virtual machine may be done at thediscretion of the scheduler mechanism regardless of the affinity oranti-affinity rule corresponding to the virtual machine being placed.

FIG. 5 illustrates a table with some examples of collocation rules 432,442 for VM groups as introduced with reference to FIG. 4. In thesimplified example shown in FIG. 5, there are three virtual machinegroups 510, GroupA 526, GroupB 527 and GroupC 530. Each of these virtualmachine groups 510 represent a container or definition that correlatevirtual machines into a group having the given group name. For each VMgroup 510 there is a collocation rule 512. In this example, thecollocation rule 512 associated with each VM group 510 is eitheraffinity or anti-affinity as shown in the table. Similarly, for each VMgroup 510 there are one or more situations 514 for the situationalenforcement policies. A few of the more common situations that couldhave an enforcement policy are given here as examples of enforcementpolicies that could be utilized by the scheduler mechanism 350 asdescribed herein to place virtual machines. In the illustrated exampleshown in FIG. 5, situations for the situational enforcement policiesinclude live migration 516, cold migration 518, rebuild 520, evacuation522 and other 524. The other situation 524 represents other situationswhich could be provided with an enforcement policy but not explicitlydescribed herein. Each of the situations 516, 518, 520, 522 and 524 hasa corresponding situational enforcement policy 515 for each VM group510. In the illustrated example, the situational enforcement policiesindicate hard enforcement or soft enforcement of the collocation rulefor the corresponding VM group 510 as shown in the table in FIG. 5.

As described above with reference to FIG. 5, the example situationalenforcement policies 514 described herein include live migration 516,cold migration 518, rebuild 520, evacuation 522 and other 524. A livemigration is a situation where an active virtual machine is moved toanother host without being halted. Conversely, a cold migration is asituation where an inactive virtual machine is migrated to a differenthost. A rebuild is a situation where a ‘host recovery’ operation isperformed to rebuild VMs from an un-operable or unhealthy host to ahealthy host. An evacuation is a situation where a user requestsevacuation of a host like in the case of placing the host in amaintenance mode. In these situations, the migrations are typicallyun-targeted. Un-targeted means the user has not specified the targethost and the VM scheduler 350 is to determine the target host.

As discussed above, the scheduler mechanism 350 allows a systemadministrator to select collocation rules and situational enforcementpolicies for a group of virtual machines. The scheduler mechanism maystore this information in a table as shown in FIG. 5. The table may bestored in memory, a computer file or in a database available to thescheduler mechanism. The scheduler mechanism thus allows a systemadministrator to set a unique enforcement policy for a group of virtualmachines for one or more various situations that may occur in thesystem. The need for situational enforcement for one VM group may differfrom the needs of another VM group for the same situation. For example,for the situation of a live migration, the system administrator mayselect a hard enforcement policy for GroupA 526 but soft enforcementpolicies for GroupB 528 as shown in FIG. 5. GroupA 526 may require hardenforcement during live migration because it is a production environmentwith strict customer requirements to not place VM workloads on the samephysical host with other customers or competitors. Conversely, GroupBmay be a test environment that does not have strict anti-affinity rulesand operations may be successful despite the non-compliance with theanti-affinity rule.

FIG. 6 illustrates a flow diagram of a method 600 for placing virtualmachines on physical resources based on collocation rules withsituational enforcement policies set by a system administrator. Themethod 600 is presented as a series of steps performed by a computersoftware program such as the scheduler mechanism 350 described above.First, create at least one virtual machine (VM) group (step 610), whichcan be done by a system administrator using a graphical user interface.Assign a collocation rule (affinity or anti-affinity) to the VM group(step 620). Set situational enforcement policies for one or moresituations for the VM group (step 630). Steps 720 and 730 can also beaccomplished by allowing a system administrator to select the policiesusing a graphical user interface. Place virtual machines on hosts basedon the collocation rules and the situational enforcement policies (step640). The method is then done.

Referring now to FIG. 7, a flow diagram shows method 700 that is anexemplary method for performing step 630 in method 600 shown in FIG. 6.Step 620 of method 600 could also be accomplished with similar steps asshown here for step 630. The method 700 is presented as a series ofsteps performed by a computer software program such as the schedulermechanism 350 described above. First, provide an administrator with aselection of situational enforcement policies for one or more situationsfor the VM group (step 710), then allow the administrator to select asituational enforcement type (hard enforcement or soft enforcement) forthe situational enforcement policies for the VM group (step 720). Themethod is done.

The claims and disclosure herein provide an apparatus and method forplacement of virtual machines on physical resources based on based oncollocation rules with situational enforcement policies set by a systemadministrator to more efficiently utilize system resources and serve theneeds of different workloads.

One skilled in the art will appreciate that many variations are possiblewithin the scope of the claims. Thus, while the disclosure isparticularly shown and described above, it will be understood by thoseskilled in the art that these and other changes in form and details maybe made therein without departing from the spirit and scope of theclaims.

The invention claimed is:
 1. An apparatus comprising: at least oneprocessor; a memory coupled to the at least one processor; a collocationrule for each of a plurality of virtual machine groups comprising aplurality of virtual machines, wherein the collocation rule is chosenfrom one of the following: affinity rule, and anti-affinity rule; aplurality of situational enforcement policies for each of the pluralityof virtual machine groups where the plurality of situational enforcementpolicies indicate how to place the plurality of virtual machines for avirtual machine group on physical host computer systems for theplurality of situations, wherein each situational enforcement policy ischosen from hard policy enforcement that indicates to strictly enforcethe collocation rule and soft policy enforcement that indicates strictenforcement of the collocation rule is not required, wherein pluralityof situations for the situational enforcement policies comprise livemigration, cold migration, rebuild, and evacuation; and a schedulermechanism residing in the memory and executed by the at least oneprocessor that places the plurality of virtual machines in the virtualmachine group on the physical host computer systems based on thecollocation rule and the plurality of situational enforcement policiesfor the plurality of situations.
 2. The apparatus of claim 1 wherein thescheduler mechanism allows a system administrator to define thecollocation rule and the plurality of situational enforcement policiesfor the virtual machine group using a graphical user interface.
 3. Theapparatus of claim 2 wherein the scheduler mechanism is part of amanagement layer of a cloud computing environment.
 4. The apparatus ofclaim 1 wherein the physical host computer systems are part of a cloudcomputing environment.
 5. The apparatus of claim 1 wherein the schedulermechanism provides a system administrator with a selection ofsituational enforcement policies for the virtual machine group for aplurality of situations.
 6. A computer-implemented method for placingvirtual machines on physical host computer systems, the methodcomprising: creating a plurality of virtual machine groups eachcomprising a plurality of virtual machines; assigning a collocation rulefor each of the plurality of virtual machine groups wherein thecollocation rule is chosen from one of the following: affinity rule, andanti-affinity rule; setting a plurality of situational enforcementpolicies for each of the plurality of virtual machine groups where theplurality of situational enforcement policies indicate how to place theplurality of virtual machines on a physical host computer system for avirtual machine group, wherein the plurality of situational enforcementpolicies include a situational enforcement policy for each of theplurality of situations that indicate how to enforce the collocationrule for a respective group for the plurality of situations, where thesituational enforcement policies for the plurality of situations areselected from hard policy enforcement and soft policy enforcement,wherein hard policy enforcement indicates to strictly enforce thecollocation rule, and soft policy enforcement indicates strictenforcement of the collocation rule is not required; placing theplurality of virtual machines on the physical host computer system basedon the collocation rule and the plurality of situational enforcementpolicies; wherein the plurality of situations for the situationalenforcement policies comprise live migration, and cold migration.
 7. Themethod of claim 6 wherein the collocation rule is assigned and theplurality of situational enforcement policies are set using a graphicaluser interface.
 8. The method of claim 6 wherein the steps are carriedout in a management layer of a cloud computing environment.
 9. Themethod of claim 6 wherein the physical host computer systems are part ofa cloud computing environment.
 10. The method of claim 6 wherein thecollocation rule is chosen from one of the following: affinity rule, andanti-affinity rule.
 11. The method of claim 6 further comprisingproviding a system administrator with a plurality of situationalenforcement policies for the virtual machine group for one or more ofthe plurality of situations.
 12. The method of claim 11 whereinplurality of situations for the plurality of situational enforcementpolicies are chosen from one of the following: rebuild, and evacuation.13. The method of claim 12 further comprising allowing the systemadministrator to select a situational enforcement policy type chosenfrom: hard policy enforcement, and soft policy enforcement.
 14. Acomputer-implemented method for placing virtual machines on physicalhost computer systems, the method comprising: creating a plurality ofvirtual machine groups each comprising a plurality of virtual machines;assigning a collocation rule for each of the plurality of virtualmachine groups wherein the collocation rule is chosen from one of thefollowing: affinity rule, and anti-affinity rule; setting a plurality ofsituational enforcement policies for each of the plurality of virtualmachine groups where the plurality of situational enforcement policiesindicate how to place the plurality of virtual machines on a physicalhost computer system for a plurality of situations for a virtual machinegroup by providing a system administrator with a plurality ofsituational enforcement policies for the virtual machine group for theplurality of situations, wherein the situational enforcement policiesfor the situations are selected from hard policy enforcement and softpolicy enforcement, wherein hard policy enforcement indicates tostrictly enforce the collocation rule, and soft policy enforcementindicates strict enforcement of the collocation rule is not required;placing the plurality of virtual machines on the physical host computersystem based on the collocation rule and the plurality of situationalenforcement policies for the respective group; wherein the plurality ofsituations for the plurality of situational enforcement policies arechosen from one of the following: live migration, cold migration,rebuild, and evacuation; wherein the collocation rule is assigned andthe plurality of situational enforcement policies are set using agraphical user interface; and wherein the steps are carried out in amanagement layer of a cloud computing environment.